IDENTIFICATION OF HUMAN HISTONE GENE REGULATORY SEQUENCES: The overall objective of our research program is to understand the structure, organization, and regulation of human histone genes. Histones are of key importance in determining structural and transcriptional properties of the genome. Additionally, histones and particularly histone synthesis appear to be intimately involved with genome replication. We have recently isolated and characterized a series of Lambda Charon 4A recombinant phage which contain human histone genes. In the studies described here, we propose to identify and characterize regulatory sequences associated with several actively transcribed human histone genes. Messenger RNA coding regions and the flanking sequences will then be identified by introduction of deletions and site-directed mutations, with assessment of transcription both in vivo and in vitro. To further define the functionality of DNA sequences involved in regulating histone gene transcription, we will exchange "regulatory" and "structural" sequences of human histone genes with those of another gene such as globin. Because at least a subset of the human histone genes are under cell cycle control, it should be possible to determine whether histone regulatory sequences can control expression of other genes in a cell cycle stage-specific manner.